[9fans] print(2)'s format

[9fans] print(2)'s format

[trebol]

Hello, this is the little story:
I usually write scripts needing numbers padded on the left with zeros, like in '%03.0f'.  In UNIX I use printf(1), but now I'm using more and more rc scripts with P9P, and I like to use Plan9 programs to make the scripts more portable to Plan9... so I tried with seq, like '9 seq -f%03.0f $i $i' or -f%03g, getting the desired output in P9P, but discovering that in Plan9, the floating point verbs doesn't include the flag '0'.
I'm really curious about this.  Anyone knows the reason of letting out this flag (and including it in P9P)?

Regards,
trebol. 

Re: [9fans] print(2)'s format

[erik quanstrom]

> Hello, this is the little story:
> I usually write scripts needing numbers padded on the left with zeros, like in '%03.0f'.  In UNIX I use printf(1), but now I'm using more and more rc scripts with P9P, and I like to use Plan9 programs to make the scripts more portable to Plan9... so I tried with seq, like '9 seq -f%03.0f $i $i' or -f%03g, getting the desired output in P9P, but discovering that in Plan9, the floating point verbs doesn't include the flag '0'.
> I'm really curious about this.  Anyone knows the reason of letting out this flag (and including it in P9P)?
>

i am not sure if there is any knock-on to this, but i think this is all that's
required.  unfortunately %06s might do some wierd things.  shouldn't
be a big issue, since that's not specified anyway,  and
	g '%0[0-9]*(\.[0-9]*)?[sq]' /sys/src
turns up nothing.

i'm considering the patch.

- erik

diff -c /n/dump/2014/0302/sys/src/libc/fmt/dofmt.c ./dofmt.c
/n/dump/2014/0302/sys/src/libc/fmt/dofmt.c:87,99 - ./dofmt.c:87,100
  int
  _fmtpad(Fmt *f, int n)
  {
- 	char *t, *s;
+ 	char *t, *s, c;
  	int i;

  	t = f->to;
  	s = f->stop;
+ 	c = f->flags&FmtZero? '0': ' ';
  	for(i = 0; i < n; i++)
- 		FMTCHAR(f, t, s, ' ');
+ 		FMTCHAR(f, t, s, c);
  	f->nfmt += t - (char *)f->to;
  	f->to = t;
  	return 0;
/n/dump/2014/0302/sys/src/libc/fmt/dofmt.c:102,114 - ./dofmt.c:103,116
  int
  _rfmtpad(Fmt *f, int n)
  {
- 	Rune *t, *s;
+ 	Rune *t, *s, r;
  	int i;

  	t = f->to;
  	s = f->stop;
+ 	r = f->flags&FmtZero? '0': ' ';
  	for(i = 0; i < n; i++)
- 		FMTRCHAR(f, t, s, ' ');
+ 		FMTRCHAR(f, t, s, r);
  	f->nfmt += t - (Rune *)f->to;
  	f->to = t;
  	return 0;
diff -c /n/dump/2014/0302/sys/src/libc/fmt/fltfmt.c ./fltfmt.c
/n/dump/2014/0302/sys/src/libc/fmt/fltfmt.c:303,309 - ./fltfmt.c:303,309
  	 * which is 341 currently.
  	 */
  	xdtoa(fmt, s, f);
- 	fmt->flags &= FmtWidth|FmtLeft;
+ 	fmt->flags &= FmtZero|FmtWidth|FmtLeft;
  	_fmtcpy(fmt, s, strlen(s), strlen(s));
  	return 0;
  }